Modeling method and apparatus for use in surgical navigation

Abstract

A modeling method for use in surgical navigation is provided. The method acquires a finite number of pre-defined points from a patient's bone and registers the points with a surgical navigation system. The navigation system generates and displays a three-dimensional image of a warped bone model that is manipulatable and accurate in at least the locations of the points taken and can be used to calculate the locations of bone cuts, implant positions and sizes, as well as display all of this information on the three-dimensional warped model.

1. A method of modeling a bone during a surgical navigation procedure, comprising:
 providing a tracking system and a modeling instrument detectable by the tracking system; 
 acquiring up to nine predefined points from a bone with the modeling instrument, the acquired points being used to generate a representative model of the bone; 
 associating the representative model of the bone with a reference bone model from a computer database associated with the tracking system; 
 warping the reference bone model to at least coincide with the representative model of the bone at the locations of the acquired predefined points; 
 displaying a three-dimensional and manipulatable image of the warped reference bone model, the image showing the acquired predefined points; 
 intra-operatively manipulating the image of the warped reference bone model to calculate a bone cut or to determine surgical information for performing the surgical procedure, the surgical information including gap analysis data, resection plane details and bone alignment angles; and 
 wherein the displayed warped reference bone model accurately represents the location of the patient's bone in real time in at least the locations of the acquired predefined points. 
 
     
     
       2. The method of  claim 1 , wherein up to seven predefined points are acquired from the bone with the modeling instrument. 
     
     
       3. The method of  claim 1 , wherein calculating a bone cut comprises analyzing the predefined points on the warped reference bone model. 
     
     
       4. The method of  claim 1 , further comprising displaying an image of an implant on the warped reference bone model. 
     
     
       5. The method of  claim 1 , further comprising displaying an image of a cutting location on the warped reference bone model. 
     
     
       6. The method of  claim 1 , wherein the bone being modeled comprises a femur. 
     
     
       7. The method of  claim 1 , wherein the bone being modeled comprises a tibia. 
     
     
       8. The method of  claim 1 , wherein at least one of the predefined points is a landmark selected from the group consisting of a femoral head landmark, a central knee landmark, a medial femoral condyle landmark, a lateral femoral condyle landmark, a medial epicondyle landmark, a lateral epicondyle landmark, a medial posterior condyle landmark, a lateral posterior condyle landmark and an anterior cortex point landmark. 
     
     
       9. An image guided surgery system, comprising:
 a tracking system having a measurement field; 
 a modeling instrument detectable by the tracking system when exposed to the measurement field; 
 means for generating a representative model of a bone while the modeling instrument acquires up to nine predefined points from the bone; 
 means for associating the representative model of the bone with a reference bone model contained within a computer database that is associated with the tracking system; 
 means for warping the reference bone model to at least coincide with the representative bone model at the locations of the acquired predefined points; 
 means for displaying a three-dimensional and manipulatable image of the warped reference bone model, the image accurately showing the location of the patient's bone in real time in at least the locations of the acquired predefined points; and 
 means for intra-operatively manipulating the image of the warped reference bone model to calculate a bone cut or to determine surgical information for performing a surgical procedure, the surgical information including gap analysis data, resection plane details and bone alignment angles. 
 
     
     
       10. The system of  claim 9 , further comprising a means for displaying an image of an implant on the warped reference bone model. 
     
     
       11. The system of  claim 9 , further comprising a means for displaying an image of a cutting location on the warped reference bone model. 
     
     
       12. The system of  claim 9 , wherein up to seven predefined points are acquired from the bone with the modeling instrument. 
     
     
       13. The method of  claim 1 , wherein from seven to nine predefined points are acquired from the bone with the modeling instrument. 
     
     
       14. The system of  claim 9 , wherein from seven to nine predefined points are acquired from the bone with the modeling instrument.